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MEASUREMENT OF PHTHALATE LEVELS IN HUMAN MILK: CONTRIBUTION FROM PLASTICS IN BREAST PUMPS, STORAGE BOTTLES AND BAGS
Citation:
HINES, E. P., R. R. BARBEE, A. M. CALAFAT, M. J. SILVA, J. A. REIDY, R. Y. WANG, L. L. NEEDHAM, AND S. E. FENTON. MEASUREMENT OF PHTHALATE LEVELS IN HUMAN MILK: CONTRIBUTION FROM PLASTICS IN BREAST PUMPS, STORAGE BOTTLES AND BAGS. Presented at EDC Forum of the 2005 Endocrine Society Meeting, San Diego, CA, June 03, 2005.
Description:
Phthalates are plasticizers used to impart flexibility in products widely used by the general population, including polyvinyl chloride, plastic toys, and medical devices. Some phthalates act as anti-androgens, and prenatal or perinatal exposure to phthalates in laboratory animals leads to testicular dysfunction. Because of the reported leaching of phthalates from plastic products, we wanted to determine if phthalate metabolite levels changed during the process of breast milk collection. The first goal of this study was to assess whether the use of a breast pump contributes to phthalate exposure in human milk during collection. The second goal of this study was to determine if phthalate levels are affected by the routine consumer handling of human milk following collection. Pooled human milk (5 donors) was used and an aliquot of milk was stored for determination of basal milk phthalate metabolite concentration. Phthalate metabolites were used as an index of phthalate exposure and they were quantified by HPLC/MS/MS (LOD 1ng/ml). Aliquots were collected following: transition through a commercial breast pump; storage in plastic bottles or bags; freezing, defrosting, and/or microwaving the milk. Milk was collected after each of 11 handling steps and each experiment was performed in triplicate. Phosphoric acid was used to control for esterase activity in the milk. Of the 9 phthalate metabolites measured, mono(2-ethylhexyl) phthalate (MEHP), monobenzyl phthalate (MBzP), and mono-isononyl phthalate (MNP) were detectable in the human milk samples. MEHP and MNP were found in all human samples. The range of MEHP in human milk was 1.1 to 10.7 ng/ml [ppb]. The mean basal (+SEM) human MEHP and MNP concentrations were 6.7+1.6 and 5.5+0.4 ppb, respectively, in samples containing phosphoric acid prior to addition to the pump, and 8+2.5 and 8.4+1 ppb, respectively, if phosphoric acid was added after passing through the pump resulting in significant effect of enzyme inhibitor (p<0.05). However, there was no significant increase in phthalate metabolite levels between aliquots collected at different steps in the procedure The data from this preliminary evaluation suggest that there is no significant increase in phthalate metabolites levels in milk after passing through a breast pump, bottles, or plastic storage bags even though these products may contain phthalates. (This abstract does not necessarily reflect EPA policy.)